Tuesday, February 22, 2011

It is always good to get out on a bike, the feeling of freedom, speed and the pure adrenaline rush of turning the cranks are always a tonic. It is even better when you are riding the bike you have constructed from the frame up. Slightly different perhaps to riding a new bike, because generally you are certain that everything is set up correctly and all you are trying to do is determine how fast it stops and how tightly you can make the turns. So perhaps it is a good thing that I rode to our local park with the kids and so stopped myself pulling any crazy tricks before I was sure of my mechanical skills. A great leveller of ability, is when you have to stop to support and encourage your 4 year old on their bike.

So what did I find out about the mechanical soundness of the bike? Well, I need to make a small adjustment to the brake and gear lever as they aren't optimal, and I haven't quite aligned the limit screw to allow a jump on to the final cog. Apart from that everything else held together fine. The wheels go muddy, I wall rolled a few steep banks and popped a few (brief) wheelies. By the end of the trip nothing was squeaking or falling off, which is a positive. I washed the wheels off, not because they were muddy, but because of the risk that some of the brown stuff came out of dogs' bottoms, and the paint stayed on. All in all a good start to a career as an amateur bike mechanic and assembler.

Next steps, well I think after the small adjustments to be done it is time to get out on some tame trails near me, and then move out to the bigger challenges after that. I also think that now might be the time to reflect on what I have learned through this process, so I suspect the next few blog posts will carry the dos and don'tsl in bike construction.

Tuesday, February 15, 2011

Swapped tyres for a thinner profile at the back, and hey presto no problems with the tyre being jammed into the frame at full inflation.. Of course now the bike just looks plain silly with a big fat free ride tyre on the front, so I will have to find a few moments to change that for a different one as well. If I had the spare cash I would buy some new ones, but as I don't I am robbing them off the old bike. A bike which will set on the work bench of the shed for awhile awaiting a new headset and a pair of forks.

The advantage of the tyre change is that suddenly I look less flashy and a little more "stealth" for riding out with all those fit young dirt jumpers. No-one will expect me to be making big air or downhilling in Scotland every summer. Certainly, not until I have invested in a full face helmet. One very bruised face from a "minor" tumble is enough thank you very much.

Sunday, February 6, 2011

Finally, the bike is complete! There are a few niggles, like the fact that it is unrideable in its current configuration, but it is complete and I am hoping that the issues can be overcome quickly and cheaply.

brake boss line up

Finally, I have brake bosses that at least partially work with the XT brake arms. If you look in the photograph you can see the three versions that I managed to get. Look at the different size of the lip next to the screw and if you can compare the profile of each boss fitting. Not all bosses are the same and so when you get to adding brake arms it is clearly a question of the right ones for the job. I'm keeping the others in my spares box for anyother job. The one to the right is from Tiawan and made of titanium, but is far better quality and has a better profile than the others. Even so it does not provide a perfect fit for the brake arms, with a small 3mm gap between the frame and the arm. I am hoping that this will not cause to much strain in braking, because if it does I will need to see if the adaptor kit works any better.

just a small gap

Confident that I would at least have some braking potential, and finding my Sunday afternoon surprisingly free, I continued on completing the last jobs on the bike. First up chain onto the bike. Simple enough, I'm not going to explain the ins and outs as it is done well enough in Zinn and in other bicycle maintance books. I had not appreciated how much you need to be an octopus though. I was most pleased that I was fixing the chain together with a powerlink and not having to force a pin into place with a chain tool. Really simple, but a little more fiddley was the task of aligning the rear derailleur (mech). Setting the high and low screws to match the limits of chain movement is simple in theory. I found that holding the derailleur over the low position and looking at where the limit screw was holding gave me more confidence that this phase was set up.

powerlink

I then needed to cut the housing for both the brakes and the gears. I wish I had a proper wire cutter for this as it was hard work with the cutter on my old pliers, but they worked adequately. Fighting to not strip the wire as you thread it through the housing is also a must. Not only does it make it difficult to thread, it will also weaken the cable. Finally, I fitted the handlebar grips, (some lizardskin ones which have lock down bolts) and adjusted the shifter and brake levers into position.

I have however, created a bike that is a little overdeveloped in the tyre department. There is an alignment issue with the rear wheel which I think is easy to sort, but there is one major problem that is preventing me from riding the P3 today. The tyres are too fat. Inflated the rear tyre is one large balloon wedged between the downstays. Not so bad at lower pressures, but it still rubs the frame badly. The original tyres that came with the wheels, I seems to remember, were fine. So I will try a switch back. In the short term there is a potential to borrow some from Uncle Riotous who is storing a load of spares. The ultimate will be a rebuild of the hub on a narrower rim. Whilst I have enjoyed assembling a bike from its components and I even feel that framebuilding might one day be an option- I have visions of being an old man with a shed in the Welsh mountains building custom frames. Wheel building is an art that requires specialisr equipment, much patience and many hours. So to rebuild the wheel I think I may need to employ my local bike shop.

P3 rebuild

current state of play

about the blog

Professor Dawkins has suggested that the act of creation is like a blind watchmaker. I have explored this idea in building a bike from second hand parts. Like the blind watchmaker I have had no idea of what is the next stage or even the correct component. Unlike the blind watchmaker I have the internet and suddenly it was a whole lot quicker.